1982—2015年气候变化和人类活动对内蒙古草地净初级生产力的影响

研究1982—2015年气候变化和人类活动对内蒙古草地净初级生产力(NPP)的影响。结果表明: 1982—1998年和1999—2015年2个时期,内蒙古草地实际NPP(ANPP)增长速率分别为1.08和1.36 g C·m^-2·a^-1,草地以恢复为主,2个时期草地恢复面积分别占研究区总面积的81.6%和76.3%;草地退化面积有增加趋势,且气候变化和人类活动对不同类型草地的影响不同。2个时期气候变化对草地恢复贡献率分别为79.3%和94.1%,气候变化是草地恢复的主要因素,其中,ANPP与降水呈显著正相关,而与温度的相关性不显著,表明降水是影响草地恢复的主要气候因子。2个时期人类活动对草地退化的贡献率分别为83.3%和87.8%,说明人类活动是导致草地退化的主要原因。气候变化对内蒙古草地恢复起主导作用,而人类活动诸如放牧数量、耕地面积和造林面积的增加,加速了草地退化。

Impacts of climate change and human activities on net primary productivity of grasslands in Inner Mongolia,China during 1982-2015

We analyzed the impacts of climate change and human activities on the net primary productivity of grasslands in Inner Mongolia during 1982-2015. The results showed that the growth rates of actual net primary productivity(ANPP) were 1.08 and 1.36 g C · m^-2·a^-1 in 1982-1998 and 1999-2015, respectively. Such changes were largely due to restoration, with restoration implementing in 81.6% and 76.3% of the total study area in 1982-1998 and 1999-2015, respectively. The area of degraded grasslands tends to increase. The effects of climate change and human activity varied across different types of grassland. Climate change was the main contributor to grassland restoration over the two periods, with the contribution rates being 79.3% and 94.1%, respectively. The ANPP was positively correlated with precipitation but not with temperature, indicating that precipitation was the main climate factor influencing grassland restoration. Human activities contributed most to grassland degradation over the two periods, with the contribute rate being 83.3% and 87.8%, respectively. Our results suggested that the climate change was the dominant contributor to grassland restoration, while human activities, such as increase in livestock numbers, cultivation and afforestation, accelerated grassland degradation.